leptos-helios 0.8.1

//! Authentication providers and implementations
//!
//! This module provides authentication providers including OAuth2, SAML,
//! and other authentication mechanisms.

use super::errors::SecurityError;
use super::types::*;
use async_trait::async_trait;
use serde::{Deserialize, Serialize};
use std::collections::HashMap;
use std::sync::Arc;
use tokio::sync::RwLock;

/// Core authentication provider trait
#[async_trait]
pub trait AuthProvider: Send + Sync {
    /// Authenticate user with credentials
    async fn authenticate(
        &self,
        credentials: &Credentials,
    ) -> Result<AuthenticationResult, SecurityError>;

    /// Validate existing token
    async fn validate_token(&self, token: &str) -> Result<User, SecurityError>;

    /// Refresh access token
    async fn refresh_token(
        &self,
        refresh_token: &str,
    ) -> Result<AuthenticationResult, SecurityError>;

    /// Logout user
    async fn logout(&self, token: &str) -> Result<(), SecurityError>;

    /// Get provider type identifier
    fn provider_type(&self) -> &'static str;
}

/// OAuth 2.0 authentication provider
pub struct OAuth2Provider {
    client_id: String,
    client_secret: String,
    authorization_url: String,
    token_url: String,
    userinfo_url: String,
    redirect_uri: String,
    scope: Vec<String>,
    token_cache: Arc<RwLock<HashMap<String, (User, u64)>>>, // token -> (user, expires_at)
}

impl OAuth2Provider {
    pub fn new(
        client_id: String,
        client_secret: String,
        authorization_url: String,
        token_url: String,
        userinfo_url: String,
        redirect_uri: String,
    ) -> Self {
        Self {
            client_id,
            client_secret,
            authorization_url,
            token_url,
            userinfo_url,
            redirect_uri,
            scope: vec![
                "openid".to_string(),
                "profile".to_string(),
                "email".to_string(),
            ],
            token_cache: Arc::new(RwLock::new(HashMap::new())),
        }
    }

    pub fn get_authorization_url(&self, state: &str) -> String {
        format!(
            "{}?client_id={}&response_type=code&redirect_uri={}&scope={}&state={}",
            self.authorization_url,
            self.client_id,
            urlencoding::encode(&self.redirect_uri),
            self.scope.join(" "),
            state
        )
    }

    pub async fn exchange_code_for_token(
        &self,
        code: &str,
    ) -> Result<OAuth2TokenResponse, SecurityError> {
        // Mock implementation - in real scenario, make HTTP request
        Ok(OAuth2TokenResponse {
            access_token: format!("access_token_{}", code),
            token_type: "Bearer".to_string(),
            expires_in: 3600,
            refresh_token: Some(format!("refresh_token_{}", code)),
            scope: Some(self.scope.join(" ")),
        })
    }

    pub async fn get_user_info(&self, _access_token: &str) -> Result<OAuth2UserInfo, SecurityError> {
        // Mock implementation - in real scenario, make HTTP request
        Ok(OAuth2UserInfo {
            sub: "user123".to_string(),
            name: "Test User".to_string(),
            email: "test@example.com".to_string(),
            email_verified: true,
            picture: Some("https://example.com/avatar.jpg".to_string()),
        })
    }

    pub async fn refresh_access_token(
        &self,
        refresh_token: &str,
    ) -> Result<OAuth2TokenResponse, SecurityError> {
        // Mock implementation - in real scenario, make HTTP request
        Ok(OAuth2TokenResponse {
            access_token: format!("new_access_token_{}", refresh_token),
            token_type: "Bearer".to_string(),
            expires_in: 3600,
            refresh_token: Some(format!("new_refresh_token_{}", refresh_token)),
            scope: Some(self.scope.join(" ")),
        })
    }
}

#[async_trait]
impl AuthProvider for OAuth2Provider {
    async fn authenticate(
        &self,
        credentials: &Credentials,
    ) -> Result<AuthenticationResult, SecurityError> {
        match &credentials.credential_type {
            CredentialType::OAuth2 => {
                // For OAuth2, we expect an authorization code
                if let Some(code) = credentials.get_data("code") {
                    let token_response = self.exchange_code_for_token(code).await?;
                    let user_info = self.get_user_info(&token_response.access_token).await?;

                    let user = User::new(
                        user_info.sub,
                        user_info.name.clone(),
                        user_info.email,
                        user_info.name,
                    );

                    let expires_at = std::time::SystemTime::now()
                        .duration_since(std::time::UNIX_EPOCH)
                        .unwrap()
                        .as_secs()
                        + token_response.expires_in as u64;

                    // Cache the token
                    {
                        let mut cache = self.token_cache.write().await;
                        cache.insert(
                            token_response.access_token.clone(),
                            (user.clone(), expires_at),
                        );
                    }

                    Ok(AuthenticationResult::success(
                        user,
                        token_response.access_token,
                        expires_at,
                    ))
                } else {
                    Err(SecurityError::authentication_failed(
                        "Missing authorization code",
                    ))
                }
            }
            _ => Err(SecurityError::authentication_failed(
                "Invalid credential type for OAuth2",
            )),
        }
    }

    async fn validate_token(&self, token: &str) -> Result<User, SecurityError> {
        let cache = self.token_cache.read().await;
        if let Some((user, expires_at)) = cache.get(token) {
            let now = std::time::SystemTime::now()
                .duration_since(std::time::UNIX_EPOCH)
                .unwrap()
                .as_secs();

            if *expires_at > now {
                Ok(user.clone())
            } else {
                Err(SecurityError::token_error("Token expired"))
            }
        } else {
            Err(SecurityError::token_error("Invalid token"))
        }
    }

    async fn refresh_token(
        &self,
        refresh_token: &str,
    ) -> Result<AuthenticationResult, SecurityError> {
        let token_response = self.refresh_access_token(refresh_token).await?;
        let user_info = self.get_user_info(&token_response.access_token).await?;

        let user = User::new(
            user_info.sub,
            user_info.name.clone(),
            user_info.email,
            user_info.name,
        );

        let expires_at = std::time::SystemTime::now()
            .duration_since(std::time::UNIX_EPOCH)
            .unwrap()
            .as_secs()
            + token_response.expires_in as u64;

        // Cache the new token
        {
            let mut cache = self.token_cache.write().await;
            cache.insert(
                token_response.access_token.clone(),
                (user.clone(), expires_at),
            );
        }

        Ok(AuthenticationResult::success(
            user,
            token_response.access_token,
            expires_at,
        ))
    }

    async fn logout(&self, token: &str) -> Result<(), SecurityError> {
        let mut cache = self.token_cache.write().await;
        cache.remove(token);
        Ok(())
    }

    fn provider_type(&self) -> &'static str {
        "oauth2"
    }
}

/// OAuth2 token response
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct OAuth2TokenResponse {
    pub access_token: String,
    pub token_type: String,
    pub expires_in: u32,
    pub refresh_token: Option<String>,
    pub scope: Option<String>,
}

/// OAuth2 user info
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct OAuth2UserInfo {
    pub sub: String,
    pub name: String,
    pub email: String,
    pub email_verified: bool,
    pub picture: Option<String>,
}

/// SAML authentication provider
pub struct SAMLProvider {
    entity_id: String,
    sso_url: String,
    slo_url: String,
    certificate: String,
    private_key: String,
    user_cache: Arc<RwLock<HashMap<String, User>>>, // assertion_id -> user
}

impl SAMLProvider {
    pub fn new(
        entity_id: String,
        sso_url: String,
        slo_url: String,
        certificate: String,
        private_key: String,
    ) -> Self {
        Self {
            entity_id,
            sso_url,
            slo_url,
            certificate,
            private_key,
            user_cache: Arc::new(RwLock::new(HashMap::new())),
        }
    }

    pub fn get_sso_url(&self, relay_state: &str) -> String {
        format!(
            "{}?SAMLRequest={}&RelayState={}",
            self.sso_url,
            urlencoding::encode(&self.create_authn_request()),
            urlencoding::encode(relay_state)
        )
    }

    fn create_authn_request(&self) -> String {
        // Mock SAML AuthnRequest - in real scenario, create proper XML
        format!("<samlp:AuthnRequest xmlns:samlp=\"urn:oasis:names:tc:SAML:2.0:protocol\" ID=\"_{}\" Version=\"2.0\" IssueInstant=\"{}\" Destination=\"{}\" AssertionConsumerServiceURL=\"{}\"><saml:Issuer xmlns:saml=\"urn:oasis:names:tc:SAML:2.0:assertion\">{}</saml:Issuer></samlp:AuthnRequest>",
                uuid::Uuid::new_v4(),
                chrono::Utc::now().to_rfc3339(),
                self.sso_url,
                self.sso_url,
                self.entity_id)
    }

    pub async fn process_saml_response(&self, _saml_response: &str) -> Result<User, SecurityError> {
        // Mock SAML response processing - in real scenario, parse and validate XML
        let user = User::new(
            "saml_user_123".to_string(),
            "saml_user".to_string(),
            "saml@example.com".to_string(),
            "SAML User".to_string(),
        );

        // Cache the user
        {
            let mut cache = self.user_cache.write().await;
            cache.insert("assertion_123".to_string(), user.clone());
        }

        Ok(user)
    }
}

#[async_trait]
impl AuthProvider for SAMLProvider {
    async fn authenticate(
        &self,
        credentials: &Credentials,
    ) -> Result<AuthenticationResult, SecurityError> {
        match &credentials.credential_type {
            CredentialType::SAML => {
                if let Some(saml_response) = credentials.get_data("saml_response") {
                    let user = self.process_saml_response(saml_response).await?;
                    let token = format!("saml_token_{}", uuid::Uuid::new_v4());
                    let expires_at = std::time::SystemTime::now()
                        .duration_since(std::time::UNIX_EPOCH)
                        .unwrap()
                        .as_secs()
                        + 3600;

                    Ok(AuthenticationResult::success(user, token, expires_at))
                } else {
                    Err(SecurityError::authentication_failed(
                        "Missing SAML response",
                    ))
                }
            }
            _ => Err(SecurityError::authentication_failed(
                "Invalid credential type for SAML",
            )),
        }
    }

    async fn validate_token(&self, token: &str) -> Result<User, SecurityError> {
        // For SAML, we'd typically validate the token differently
        // This is a simplified implementation
        if token.starts_with("saml_token_") {
            // Mock user for SAML token
            Ok(User::new(
                "saml_user_123".to_string(),
                "saml_user".to_string(),
                "saml@example.com".to_string(),
                "SAML User".to_string(),
            ))
        } else {
            Err(SecurityError::token_error("Invalid SAML token"))
        }
    }

    async fn refresh_token(
        &self,
        _refresh_token: &str,
    ) -> Result<AuthenticationResult, SecurityError> {
        Err(SecurityError::token_error(
            "SAML tokens cannot be refreshed",
        ))
    }

    async fn logout(&self, _token: &str) -> Result<(), SecurityError> {
        // SAML logout would typically involve SLO (Single Logout)
        Ok(())
    }

    fn provider_type(&self) -> &'static str {
        "saml"
    }
}

/// Simple username/password authentication provider
pub struct UsernamePasswordProvider {
    users: Arc<RwLock<HashMap<String, (String, User)>>>, // username -> (password_hash, user)
}

impl UsernamePasswordProvider {
    pub fn new() -> Self {
        Self {
            users: Arc::new(RwLock::new(HashMap::new())),
        }
    }

    pub async fn add_user(&self, username: String, password: String, user: User) {
        let password_hash = self.hash_password(&password);
        let mut users = self.users.write().await;
        users.insert(username, (password_hash, user));
    }

    fn hash_password(&self, password: &str) -> String {
        // In real implementation, use proper password hashing like bcrypt
        format!("hash_{}", password)
    }

    fn verify_password(&self, password: &str, hash: &str) -> bool {
        // In real implementation, use proper password verification
        hash == &format!("hash_{}", password)
    }
}

#[async_trait]
impl AuthProvider for UsernamePasswordProvider {
    async fn authenticate(
        &self,
        credentials: &Credentials,
    ) -> Result<AuthenticationResult, SecurityError> {
        match &credentials.credential_type {
            CredentialType::UsernamePassword => {
                if let (Some(username), Some(password)) =
                    (&credentials.username, &credentials.password)
                {
                    let users = self.users.read().await;
                    if let Some((password_hash, user)) = users.get(username) {
                        if self.verify_password(password, password_hash) {
                            let token = format!("token_{}", uuid::Uuid::new_v4());
                            let expires_at = std::time::SystemTime::now()
                                .duration_since(std::time::UNIX_EPOCH)
                                .unwrap()
                                .as_secs()
                                + 3600;

                            Ok(AuthenticationResult::success(
                                user.clone(),
                                token,
                                expires_at,
                            ))
                        } else {
                            Err(SecurityError::authentication_failed("Invalid password"))
                        }
                    } else {
                        Err(SecurityError::authentication_failed("User not found"))
                    }
                } else {
                    Err(SecurityError::authentication_failed(
                        "Missing username or password",
                    ))
                }
            }
            _ => Err(SecurityError::authentication_failed(
                "Invalid credential type for username/password",
            )),
        }
    }

    async fn validate_token(&self, token: &str) -> Result<User, SecurityError> {
        // Simple token validation - in real implementation, use JWT or similar
        if token.starts_with("token_") {
            // Mock user for token
            Ok(User::new(
                "user123".to_string(),
                "testuser".to_string(),
                "test@example.com".to_string(),
                "Test User".to_string(),
            ))
        } else {
            Err(SecurityError::token_error("Invalid token"))
        }
    }

    async fn refresh_token(
        &self,
        _refresh_token: &str,
    ) -> Result<AuthenticationResult, SecurityError> {
        Err(SecurityError::token_error("Token refresh not supported"))
    }

    async fn logout(&self, _token: &str) -> Result<(), SecurityError> {
        Ok(())
    }

    fn provider_type(&self) -> &'static str {
        "username_password"
    }
}